Electrical stimulation in the lateral hypothalamic area of rats can cause permanent changes in the animals' willingness to drink alcohol. Rats given mild hypothalamic stimulation daily for 30 days develop a permanent preference for alcohol; they will drink 20 per cent alcohol solutions exclusively when given a free choice of water. The purpose of the proposed research is to explore this phenomenon in terms of the organization of the neural substrate underlying the effect. Two lines of attack are proposed. The first involves the determination of whether similar stimulation at other brain sites will also alter alcohol preference. The plan is to systematically evaluate the effects of stimulation of other sites, beginning with sites that have functional characteristics in common with the lateral hypothalamus. Stimulation in the hypothalamus may be effective because it activates homeostatic mechanisms or non-adrenergic circuits, or because it sets up epileptiform afterdischarge; the first extrahypothalamic sites to be stimulated will be sites where stimulation also has some of these properties. The second line of research involves studying the effects of hypothalamic stimulation in animals that have lesions in other brain structures. The structures lesioned will be chosen as a function of the results of the stimulation studies in the hope that the data from the two lines of study will indicate the nature of the neural circuitry underlying the effect.